John Williamson’s notes from his presentation on Improving Landscape/Aerial Photographs are available here.
Here are links to the original photo and the Photoshop Elements Photoshop Elements psd file John created will so you can download the files and try the techniques yourself. Note that the psd file is stored on google drive. To download, left click on the above link then click on the blue “Download” button,
This article from Adobe explains how to remove haze using the haze filter built into the latest versions of Photoshop and Lightroom.